1. Technical Field
The present invention relates to an article alignment apparatus used to align an article on a conveyor.
2. Description of the Related Art
Known article alignment apparatuses are used to align articles along an advancing direction of conveyors by industrial robots. For example, an article alignment apparatus is known, in which articles are successively placed on a bucket conveyor provided with buckets for accommodating the articles at regular intervals. An article alignment apparatus is known, in which articles are successively placed at the same location in an advancing direction of a belt conveyor (see JP 2002-316716 A).
When articles are moved between conveyors, the articles are sometimes required to be aligned at predetermined intervals for a next process. However, when containers, such as trays, aligned in predetermined intervals are used for aligning articles, it is necessary to collect the containers in a post-process and to install a phototube sensor or the like for detecting positions of the trays, and thus the cost tends to increase.
According to a known technique for successively placing an article at the same location, an interval of the articles in a conveyance direction changes depending on a conveyance speed of the conveyor and a cycle time of a picking up process and a placing process of the article by a robot. Thus, the intervals between the articles need to be corrected in the post-process. When a conveyor which performs pitch feeding at a predetermined interval is used, articles can be aligned at regular intervals. However, there is a need to use the conveyor driven by an expensive servomotor, and thus the cost tends to increase.
According to a technique in which marks applied to a belt of a conveyor at predetermined intervals are detected by a phototube sensor in order to align articles based on the detection result, it is necessary to apply the marks to the belt every time it is replaced. Further, if the mark disappears, the article cannot be aligned as intended.
Therefore, there is a need for an article alignment apparatus with a simplified configuration, which can align articles at predetermined intervals.